[NSRCA-discussion] YS 140 FZ: loads up and dies 2500 - 4500 rpm

[Ron Van Putte]

Before this is done, there will be recommendations to replace  
everything below the plug and then put in a new plug.  <BG>

Seriously, the diaphragm could be bad or the plunger could be  
sticking in the pressure regulator.   If the diaphragm looks good, it  
is probably OK.  If you remove the plunger (paying attention to the  
orientation of the spring) and find "green gunk" on the stem, the  
plunger will stick intermittently. Clean it.

Ron

On Feb 2, 2009, at 5:32 PM, Ed White wrote:

> That's my vote, ring and probably bearings, if the engine has any  
> serious time on it.
>
> Not only the ring but if the slot for the ring is also worn (the  
> ring has a sloppy fit in the piston slot and can move up and down  
> visibly at all), you may need a new piston as well.
>
> Ed
>
> From: Derek Koopowitz <derekkoopowitz at gmail.com>
> To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
> Sent: Monday, February 2, 2009 2:19:14 PM
> Subject: Re: [NSRCA-discussion] YS 140 FZ: loads up and dies 2500 -  
> 4500 rpm
>
> I would suggest replacing the piston ring and perhaps even the  
> bearings.
>
> From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca- 
> discussion-bounces at lists.nsrca.org] On Behalf Of  
> adriancwong at earthlink.net
> Sent: Monday, February 02, 2009 12:09 PM
> To: paul.horan at sbcglobal.net; General pattern discussion
> Subject: Re: [NSRCA-discussion] YS 140 FZ: loads up and dies 2500 -  
> 4500 rpm
>
> What fuel are you using? Check the exhaust valve for carbon deposit  
> and header opening for clogging.
>
> The surging could be uneven contact point on the valve cover. Wet  
> sand it lightly with 400 sand paper on smooth surface until surface  
> shines.
>
> Adrian
>
>
> -----Original Message-----
> From: Paul Horan
> Sent: Feb 2, 2009 11:18 AM
> To: General pattern discussion
> Subject: [NSRCA-discussion] YS 140 FZ: loads up and dies 2500 -  
> 4500 rpm
>
>     The problem is a YS 140 FZ that runs fine at idle and 40 to  
> 100% throttle but loads up around 2500 - 4500 rpm.  This is  
> especially nasty since that is the rpm range for a smooth takeoff,   
> once it goes to full throttle the engine does not develop full  
> power (about 40% power) and dies.   Plenty of smoke trail so it is  
> not going lean.
>    Another symptom is on the ground running  2500 - 4500 rpm the  
> rpm is not steady.
> Help,
> Paul
> NSRCA 3606
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